Wang Manna, Ateia Mohamed, Hatano Yuta, Yoshimura Chihiro
Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan.
United States Environmental Protection Agency, Center for Environmental Solutions & Emergency Response, Cincinnati, OH, USA.
Environ Sci (Camb). 2022 May 19;8(7):1521-1534. doi: 10.1039/d1ew00945a.
Bacterial regrowth after water/wastewater disinfection poses severe risks to public health. However, regrowth studies under realistic water conditions that might critically affect bacterial regrowth are scarce. This study aimed to assess for the first time the regrowth of () in terms of its viability and culturability in environmental waters after chlorine disinfection, which is the most widely used disinfection method. Post-chlorination regrowth tests were conducted in 1) standard 0.85% NaCl solution, 2) river water receiving domestic wastewater effluents, and 3) river water that is fully recharged by domestic wastewater effluents. The multiplex detection of plate count and fluorescence-based viability test was adopted to quantify the culturable and viable to monitor the regrowth process. The results confirmed that chlorine treatment (0.2, 0.5 and 1.0 mg L initial free chlorine) induced more than 99.95% of to enter a viable but non-culturable (VBNC) state and the reactivation of VBNC is presumably the major process of the regrowth. A second-order regrowth model well described the temporal shift of the survival ratio of culturable after the chlorination (: 0.73-1.00). The model application also revealed that the increase in initial chlorine concentration and chlorine dose limited the maximum regrowth rate and the maximum survival ratio, and the regrowth rate and percentage also changed with the water type. This study gives a better understanding of the potential regrowth after chlorine disinfection and highlights the need for investigating the detailed relation of the regrowth to environmental conditions such as major components of water matrices.
水/废水消毒后细菌的再生长对公众健康构成严重风险。然而，在可能对细菌再生长产生关键影响的实际水条件下进行的再生长研究却很少。本研究旨在首次评估在氯消毒（最广泛使用的消毒方法）后，环境水体中（）的活力和可培养性方面的再生长情况。在以下三种水体中进行了后氯化再生长试验：1）标准0.85%氯化钠溶液，2）接纳生活污水排放的河水，3）完全由生活污水排放补给的河水。采用平板计数和基于荧光的活力检测的多重检测方法来量化可培养和存活的（），以监测再生长过程。结果证实，氯处理（初始游离氯浓度为0.2、0.5和1.0 mg/L）使超过99.95%的（）进入存活但不可培养（VBNC）状态，VBNC（）的再活化可能是再生长的主要过程。一个二阶再生长模型很好地描述了氯化后可培养（）存活率的时间变化（相关系数：0.73 - 1.00）。模型应用还表明，初始氯浓度和氯剂量的增加限制了最大再生长速率和最大存活率，且再生长速率和百分比也随水体类型而变化。本研究更好地理解了氯消毒后的潜在再生长情况，并强调了研究再生长与环境条件（如水基质的主要成分）之间详细关系的必要性。
